to allow crews to complete a track and timber replacement project and perform minor structural repairs. The Viaduct will be closed through November 2013. During this four-month period, shuttle buses will replace train service between NTC and Bridgeport.

The Viaduct rehabilitation is necessary for SEPTA to be able to continue NHSL train service between NTC and Bridgeport.

"The bridge was built in 1911 and is showing signs of deterioration like cracks, spalling concrete and corrosion," said Jeff Knueppel, SEPTA's deputy general manager. "More importantly, the bridge ties that sit directly upon the steel structure and hold the rail in place are rotting and failing."

A significant loss of capital funding through the past three years has forced SEPTA to defer major construction to the viaduct, despite designs for timber deck replacement and structural rehabilitation programs having been complete since 2011. Instead, SEPTA has implemented a targeted timber repair plan to maintain service via the bridge. These temporary repair measures included installing supplemental steel ties between existing ties and injecting epoxy into the voids of existing spike holes on all ties to secure spikes to the ties. SEPTA crews conducted daily track inspections and a 15-mile-per-hour speed restriction was instituted for trains crossing the bridge.

"We have exhausted all possible temporary timber repair measures," said Knueppel. "Without full timber replacement, we would have no choice but to permanently close the bridge."

SEPTA had previously repaired the viaduct twice before. In 1985, the bridge timbers, rail and power delivery system were completely replaced and the steel was painted and repaired. In 2009, the bridge piers were reinforced against scour. The current project will include the replacement of all bridge timbers, as well as the track level walkway and railing system and some structural repairs. The $7.5-million project will be completed by Railworks Track Systems.

On weekdays during construction, trains will operate between 69th Street Transportation Center and Bridgeport Station. On weekends, trains will operate between 69th Street Transportation Center and Hughes Park Station.